Microbiologic characteristics and antibiotic resistance rates of diabetic foot infections

Microbiological Species and Antibiotic Resistance in Diabetic and Nondiabetic Lower Extremity Wounds: A Comparative Cross-Sectional Study

Severe lower extremity wounds have an increased risk of complications and limb loss. The aim of this study was to evaluate and compare the microbiological profile and antibiotic resistance of wounds in diabetic and nondiabetic patients. A cross-sectional comparative study was carried out at a public hospital including 111 patients with moderate to severe wound infections. Tissue samples were collected during a surgical procedure. One hundred and four patients (94%) had positive cultures and 88 (79%) had a Gram-negative microorganism. Among the 185 cultured microorganisms, 133 (72%) were Gram-negative species. Pseudomonas aeruginosa (23 cases) was the most isolated Gram-negative species, and Enterococcus faecalis (26 cases) was the most prevalent Gram-positive species. Among 185 isolated species, 45 (24%) were extended-spectrum beta-lactamase producers, 23 (12%) were carbapenem-resistant, and 5 (3%) were methicillin-resistant Staphylococcus aureus. Findings revealed that there was no significant difference in the microbiological profile and antibiotic resistance among patients with lower extremity wounds whether they were diabetic or nondiabetic.

Enterococci in Diabetic Foot Infections: Prevalence, Clinical Characteristics, and Outcomes

Background

Diabetic foot infections (DFIs) are frequently polymicrobial, yet the relevance of each isolated pathogen, remains ill-defined. Specifically, the prevalence and pathogenicity of enterococcal DFIs and the impact of targeted antienterococcal treatment remain elusive.

Methods

We collected demographic, clinical, and outcome-related data on patients admitted with DFIs to the Hadassah Medical Center diabetic foot unit between 2014 and 2019. The primary outcome was a composite of in-hospital death or major amputation. Secondary outcomes included any amputation, major amputation, length of stay (LOS), and 1-year major amputation or mortality rate.

Results

Enterococci were isolated in 35% of 537 eligible DFI case patients, who were notable for a higher prevalence of peripheral vascular disease, increased levels of C-reactive protein, and higher Wagner scores. Infection in enterococci-positive individuals was mostly polymicrobial (96.8% vs 61.0% in non-enterococci-infected patients; P < .001). Enterococci-infected patients were more likely to undergo amputation (72.3% vs 50.1%; P < .001) and had longer hospital stays (median LOS, 22.5 vs 17 days; P < .001), but the primary end point of major amputation or in-hospital death did not differ between groups (25.5% vs 21.0%; P = .26). Appropriate antienterococcal antibiotics were used in 78.1% of enterococci-infected patients and, compared with results in untreated patients, were associated with a trend toward a lower rate of major amputations (20.4% vs 34.1%; P = .06) but longer hospitalization (median LOS, 24 vs 18 days; P = .07).

Conclusions

Enterococci are common in DFIs and associated with higher rates of amputation and longer hospitalization. A reduction in major amputation rates with appropriate enterococci treatment is suggested retrospectively, meriting validation by future prospective studies.

Development and Characterization of Hydroxyethyl Cellulose-Based Gels Containing Lactobacilli Strains: Evaluation of Antimicrobial Effects in In Vitro and Ex Vivo Models

This study aimed to develop a hydroxyethyl cellulose-based topical formulation containing probiotics and to evaluate its antimicrobial action using in vivo and ex vivo models. Initially, the antagonistic effects of Lacticaseibacillus rhamnosus ATCC 10863, Limosilactobacillus fermentum ATCC 23271, Lactiplantibacillus plantarum ATCC 8014 and Lactiplantibacillus plantarum LP-G18-A11 were analyzed against Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae ATCC 700603, Staphylococcus aureus ATCC 27853 and Pseudomonas aeruginosa ATCC 2785. The best action was seen for L. plantarum LP-G18-A11, which presented high inhibition against S. aureus and P. aeruginosa. Then, lactobacilli strains were incorporated into hydroxyethyl cellulose-based gels (natrosol); however, only the LP-G18-A11-incorporated gels (5% and 3%) showed antimicrobial effects. The LP-G18-A11 gel (5%) maintained its antimicrobial effects and viability up to 14 and 90 days at 25 °C and 4 °C, respectively. In the ex vivo assay using porcine skin, the LP-G18-A11 gel (5%) significantly reduced the skin loads of S. aureus and P. aeruginosa after 24 h, while only P. aeruginosa was reduced after 72 h. Moreover, the LP-G18-A11 gel (5%) showed stability in the preliminary and accelerated assays. Taken together, the results show the antimicrobial potential of L. plantarum LP-G18-A11, which may be applied in the development of new dressings for the treatment of infected wounds.

Pharmacokinetics and soft-tissue distribution of tebipenem pivoxil hydrobromide using microdialysis: a study in healthy subjects and patients with diabetic foot infections

OBJECTIVE

Tebipenem pivoxil hydrobromide is a novel oral carbapenem prodrug of tebipenem, the active moiety. We assessed tebipenem steady-state pharmacokinetics in the skin and soft tissue in healthy subjects and infected patients with diabetes using in vivo microdialysis.

METHODS

Six healthy subjects and six patients with an ongoing diabetic foot infection (DFI) received tebipenem pivoxil hydrobromide 600 mg orally every 8 h for three doses. A microdialysis probe was inserted in the thigh of healthy subjects or by the wound margin in patients. Plasma and dialysate samples were obtained immediately prior to the third dose and sampled over 8 h.

RESULTS

Tebipenem plasma protein binding (mean ± SD) was 50.2% ± 2.4% in healthy subjects and 53.5% ± 5.6% in infected patients. Mean ± SD tebipenem pharmacokinetic parameters in plasma for healthy subjects and infected patients were: maximum free concentration (fCmax), 3.74 ± 2.35 and 3.40 ± 2.86 mg/L, respectively; half-life, 0.88 ± 0.11 and 2.02 ± 1.32 h; fAUC0-8, 5.61 ± 1.64 and 10.01 ± 4.81 mg·h/L. Tebipenem tissue AUC0-8 was 5.99 ± 3.07 and 8.60 ± 2.88 mg·h/L for healthy subjects and patients, respectively. The interstitial concentration-time profile largely mirrored the free plasma profile within both populations, resulting in a penetration ratio of 107% in healthy subjects and 90% in infected patients.

CONCLUSIONS

Tebipenem demonstrated excellent distribution into skin and soft tissue of healthy subjects and patients with DFI following oral administration of 600 mg of tebipenem pivoxil hydrobromide.

Microbiology of Diabetic Foot Infections in a Tertiary Care Hospital in São Paulo, Brazil

Diabetic foot infections (DFIs) are one of the causes of hospitalization in diabetic patients and, when this occurs, empirical antibiotic therapy is necessary. We have conducted a retrospective study of patients with DFI that required hospitalization to evaluate microbiologic profile and the susceptibility pattern of these infections. We evaluated 320 patients, of which 223 (69.7%) were male with a media age of 71 years with 276 isolates. Gram-positive bacteria were responsible for 188 (68.1%) of the isolates, while Gram-negative bacilli were responsible for 88 (31.9%). E. faecalis was the most prevalent pathogen, followed by S. aureus and coagulase negative Staphylococci. Among Gram-negative pathogens, P. aeruginosa was the most prevalent agent. Regarding the susceptibility profile, we found ampicillin-sensitive enterococci in 89% of the cases, oxacillin-sensitive S. aureus in 47%, but in coagulase-negative staphylococci, oxacillin was sensible only in 20%. The susceptibility profile of Gram-negatives was very good with 76% susceptibility of P. aeruginosa to ceftazidime and meropenem. The other prevalent Enterobacterales had great susceptibility to ceftazidime, piperacillin-tazobactam and 100% susceptibility to meropenem, with the exception of K. pneumoniae, which had 75% susceptibility to meropenem. Knowledge of microbiological profile and susceptibility patterns of patients with DFIs is useful to guide empirical therapy.

Phenotypic profile and antibiogram of biofilm-producing bacteria isolates from diabetic foot ulcers in Zaria, Nigeria

Background

Diabetic foot ulcers (DFUs) present with high morbidity and reduce patient's quality of life. There is a gross paucity of data on biofilm-producing bacteria in DFU Infection in North-Western Nigeria. The study sought to determine the biofilm-forming ability of bacteria isolates from DFUs and determine their antimicrobial susceptibility pattern in Zaria, North-Western Nigeria.

Materials and Methods

This hospital-based cross-sectional study of patients with DFUs was conducted from June 2018 to February 2020. Consecutive biopsies were aseptically collected. Bacteria were isolated and identified using a Microgen kit. Biofilm forming ability and antibiogram of isolates were determined using microtitre plate and disk diffusion methods, respectively.

Results

Of the 225 participants enrolled, males constituted the majority, 144 (64.0%) with 88 (36.0%) females, the median age of participants was 54 (48-60) years, and the age range was 36-77 years. A total of 172 bacteria were isolated, and 123 (71.5%) were biofilm producers. Staphylococcus aureus (26.7%) was the highest biofilm producer, while Citrobacter freundii and Stenotrophomonas maltophilia were the least biofilm producers, 1 (0.6%) each. A disproportionate resistance pattern was demonstrated among the biofilm and non-biofilm producers against the cephalosporins tested, ceftazidime (68% vs. 18%), ceftriaxone (50% vs. 8.0%) and cefotaxime (21% vs. 0.0%). About 46% and 68% of the biofilm producers were resistant to gentamycin and ciprofloxacin, respectively. While only 2% of the non-biofilm producers were resistant to imipenem, 11% of the biofilm producers were resistant to it.

Conclusion

These findings revealed a high proportion of biofilm-producing bacteria and were more resistant than non-biofilm producers.